AAS Meeting #193 - Austin, Texas, January 1999
Session 6. Nearby AGN I - Dust, Gas, Obscuration and Fuelling
Display, Wednesday, January 6, 1999, 9:20am-6:30pm, Exhibit Hall 1

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[6.10] Are there two populations of X-ray absorbers in Seyfert 2 galaxies?

J.M. Gelbord (JHU), K.A. Weaver (GSFC/JHU)

The canonical unified model for Seyfert galaxies (Antonucci, 1993, ARA&A 31, 473) posits the existance of a nuclear torus which blocks the direct line of sight to the central engine of type 2 Seyferts. However, another possibility would be that in at least some Seyfert galaxies the obscuring body could be the disk of the host galaxy (Schmitt et al., 1997, ApJ 477, 623). The column densities of the putative tori should be a few orders of magnitude larger than those of the host galaxy planes, so we would expect a bimodal distribution of NH columns if either of these absorbers could be responsible.

Starting with the subset of the Schmitt et al. sample for which ASCA data is available, we are measuring the NH column densities using a variety of spectral models. The resulting distribution of column densities is then interpreted with consideration of both optically observed galactic inclinations and possible nuclear torus orientations implied from observed radio elongation axes. This work is being done as a part of a thesis project to examine the emission and absorption features in the X-ray spectra of a large sample of Seyfert galaxies, and to combine this data with observations made in other wavebands in order to put constraints on the unified model of Seyfert galaxies.

The author(s) of this abstract have provided an email address for comments about the abstract: jonathan@jhu.edu

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